Modes of adherence of Helicobacter pylori to gastric surface epithelium ingastroduodenal disease: A possible sequence of events leading to internalisation

We have investigated various modes of adherence of Helicobacter pylori to t he human gastric epithelium, using transmission electron microscopy, in bio psies from nine patients with peptic ulcer disease and from four patients w ith chronic active gastritis. H. pylori was demonstrated in abundance in al l cases within the surface mucous layer. In all ulcer- and in one out of fo ur gastritis patients H. pylori was shown in close proximity to the gastric epithelium, with concurrent alterations in the configuration of microvilli and the apical cytoplasmic region of gastric cells. Previously described m odes of H. pylori adherence were confirmed, such as loose attachment with f ibrillar-like strands, firm attachment with pedestal formation, invasion in the intercellular spaces, and invagination with "cup" formation. Moreover, in many cases a fusion between the bacterial outer layer and gastric cell membranes was evident. In four cases (31%; three with active and one with p ast ulcer disease) viable H. pylori was found in the cytoplasm of gastric m ucous cells. Our results support the hypothesis that the different modes of adherence of H. pylori represent a stepwise, possibly sequential, process which in a significant number of cases leads to internalisation of the orga nism. The invariable occurrence of adhesion and more frequent internalisati on of H. pylori in ulcer patients may suggest a link with the pathogenesis of peptic ulcer disease.